From f5a9762b280cd525b807ea7dcd4a6beb7b1ea308 Mon Sep 17 00:00:00 2001
From: Kyle Isom <coder@kyleisom.net>
Date: Thu, 14 Jan 2016 17:44:30 -0800
Subject: [PATCH] Add pem2bin, a utility for dumping the contents of PEM
 blocks.

---
 README.md           |  1 +
 cmd/pem2bin/README  |  8 ++++++++
 cmd/pem2bin/main.go | 39 +++++++++++++++++++++++++++++++++++++++
 3 files changed, 48 insertions(+)
 create mode 100644 cmd/pem2bin/README
 create mode 100644 cmd/pem2bin/main.go

diff --git a/README.md b/README.md
index 43c85ce..7896b3b 100644
--- a/README.md
+++ b/README.md
@@ -18,6 +18,7 @@ Contents:
                     certificate request.
         fragment/   Print a fragment of a file.
         jlp/        JSON linter/prettifier.
+	pem2bin/    Dump the binary body of a PEM-encoded block.
         pembody/    Print the body of a PEM certificate.
         showimp/    List the external (e.g. non-stdlib and outside the
                     current working directory) imports for a Go file.
diff --git a/cmd/pem2bin/README b/cmd/pem2bin/README
new file mode 100644
index 0000000..9f7cee6
--- /dev/null
+++ b/cmd/pem2bin/README
@@ -0,0 +1,8 @@
+pem2bin
+
+This is a utility that strips the PEM-encoding from a file and dumps
+the binary body to disk. The resulting filename is the original pathname
+with ".bin" appended. Note that only the first PEM block in a file will
+be decoded.
+
+Usage: pem2bin paths*
diff --git a/cmd/pem2bin/main.go b/cmd/pem2bin/main.go
new file mode 100644
index 0000000..b7594a8
--- /dev/null
+++ b/cmd/pem2bin/main.go
@@ -0,0 +1,39 @@
+package main
+
+import (
+	"encoding/pem"
+	"flag"
+	"fmt"
+	"io/ioutil"
+	"os"
+)
+
+var ext = ".bin"
+
+func stripPEM(path string) error {
+	data, err := ioutil.ReadFile(path)
+	if err != nil {
+		return err
+	}
+
+	p, rest := pem.Decode(data)
+	if len(rest) != 0 {
+		fmt.Fprintf(os.Stderr, "[WARNING] extra data in PEM file\n")
+		fmt.Fprintf(os.Stderr, "          (only the first object will be decoded)\n")
+	}
+
+	return ioutil.WriteFile(path+ext, p.Bytes, 0644)
+}
+
+func main() {
+	flag.Parse()
+
+	for _, path := range flag.Args() {
+		err := stripPEM(path)
+		if err != nil {
+			fmt.Fprintf(os.Stderr, "processing %s failed: %v\n", path, err)
+		} else {
+			fmt.Println(path, "->", path+ext)
+		}
+	}
+}